1. Field of the Invention
The present invention relates to a unitary air conditioner widely used in North America, and, more particularly, to a unitary air conditioner comprising a 1-stage indoor unit, to which a 2-stage thermostat or a variable-capacity outdoor unit is connected.
2. Description of the Related Art
FIG. 1 is a control circuit block diagram of a conventional 1-stage unitary air conditioner showing connection of principal circuit terminals.
As shown in FIG. 1, the 1-stage unitary air conditioner is constructed such that the 1-stage unitary air conditioner receives an operation signal Y or a stop signal from a 1-stage thermostat 11, which is mounted in a room, for operating a 1-stage indoor unit 13 and a 1-stage outdoor unit 15.
The 1-stage unitary air conditioner with the above-stated construction is an air-conditioning system widely used as one of household appliances in North America, such as the United States of America. According to an ON/OFF operation signal from the 1-stage thermostat 11, the 1-stage indoor unit 13 and the 1-stage outdoor unit 15 are turned ON/OFF while the capacities of the 1-stage indoor unit 13 and the 1-stage outdoor unit 15 are not changed. In the 1-stage indoor unit 13 is mounted an indoor fan 17. In the 1-stage outdoor unit 15 are mounted a compressor (not shown) and an outdoor fan (not shown).
FIG. 2 is a control circuit block diagram of a conventional 2-stage unitary air conditioner showing connection of principal circuit terminals.
As shown in FIG. 2, the 2-stage unitary air conditioner comprises a 2-stage thermostat 21. The 2-stage unitary air conditioner is constructed such that a 1-stage indoor unit 23 and a 1-stage outdoor unit 25 are operated in a high or low operation stage, while the capacities of the 2-stage indoor unit 23 and the 2-stage outdoor unit 25 are changed, according to a high operation signal Y2 or a low operation signal Y1 from the 2-stage thermostat 21. In the 2-stage indoor unit 23 is mounted an indoor fan 27, which is rotated such that flow rate of air can be adjusted to high, middle, and low flow rates.
In the above-described conventional unitary air conditioners, however, the indoor and outdoor units are connected to each other only if the indoor and outdoor units have the same stage(s). Consequently, the indoor and outdoor units are not connected to each other if the indoor and outdoor units have different stages.
For the 1-stage unitary air conditioner, for example, the 1-stage indoor unit 13 and the 1-stage outdoor unit 15 are connected to the 1-stage thermostat 11. For the 2-stage unitary air conditioner, on the other hand, the 2-stage indoor unit 23 and the 2-stage outdoor unit 25 are connected to the 2-stage thermostat 21. As a result, wide adaptability of the conventional unitary air conditioners is limited.